1. Field of the Invention
The invention relates generally to a press-fit pin, which is press-fitted into a through-hole disposed on a printed circuit board.
2. Background Art
In recent years, increasing awareness of environmental issues has focused attention on a junction technique using a press-fit pin or compliant pin as alternative to the soldering junction technique using lead material.
The press-fit pin junction technique is to mechanically fix a press-fit pin or compliant pin, which is an acicular terminal given the property of compressive elasticity, onto a printed circuit board by way of inserting the press-fit pin into a through-hole, whose diameter is slightly smaller than the width of the press-fit pin, of the printed circuit board, thereby ensuring a frictional force. A component such as a male connector is attached to the press-fit pin disposed on the print circuit board, thereby allowing lead-free mechanical and electrical interconnection.
The press-fit pin includes a press-fit portion to be in pressure contact with an internal surface of the through-hole of the printed circuit board. The press-fit portion may be manufactured by stamping out a pin-like shape from a metal plate and thereafter forming a slit (needle eye) at a center of the resulting pin along a longitudinal direction.
Securing a sufficient effective contact area and maintaining an adequate contact pressure are necessary for assuring fundamental performance in reliability of connection of the press-fit pin. For example, if the contact pressure is too small, the effective contact area is insufficient, resulting in deterioration in the reliability of the connection. In contrast, in a case where the contact pressure increases by using a press-fit pin in a larger size and shape in order to obtain higher contact pressure, a portion of the printed circuit board may be cracked due to improper insertion force. In addition, the press-fit pin may be damaged. This may cause an increase in electrical contact resistance.